The present invention relates to a device for automatic tuning of a string instrument, in particular, a guitar, with a detection device for detecting a tone generated when a string is struck as well as for the output of a digital signal corresponding to the detected tone, memory device for storing preset digital signals, which correspond to a desired tone, comparison device for comparing the digital signal output by the detection device with a digital signal stored in the memory device and corresponding to the desired tone, an adjustment device for changing the tension of the strings, at least one drive for driving the adjustment device and a controller, which is connected to the comparison device and which controls the one or more drives via a bus line with reference to a deviation determined in the comparison device between the signals representing the generated tone and the desired tone. It further relates to a method for automatic tuning of a string instrument, in which a string to be tuned is struck, the tone generated by the string is detected by a detection device and converted into a corresponding first digital signal and the first digital signal is compared with a preset, second digital signal corresponding to a desired tone and a necessary change in the string tension is calculated in a controller from the comparison.
In general, tuning instruments requires, in addition to a trained ear, a large amount of time, especially for untrained, for example, amateur instrumentalists. In the classic method of tuning “by hand,” the musician works with a tuning fork, which gives a desired tone when it is struck, and the pitch of the relevant string is adjusted by changing the string length or string tension. By striking the string and the tuning fork several times, the result is equalized until the desired tuning of the string is achieved. Starting from this tuning, the other strings are then tuned.
On the one hand, because the strings of the instrument must always be tuned regularly due to an ever present elasticity of the material and, on the other hand, because the strings are also variable in length as a function of the climatic conditions (on the stage of a concert hall, a guitar string will expand with the heat and humid air in comparison with the conditions in the relatively dry and cool practice room), frequent tuning is necessary. New strings must also be tuned after they are installed.
To create a simplification here, in U.S. Pat. No. 4,803,908 a device for automatic tuning of a string instrument was proposed. In this device, all of the strings are struck simultaneously on a guitar with an aid, which is called “strummer” in this publication and which is arranged in the body of the guitar. Electronics detects the tones, compares them with the desired setting, and controls an adjustment device engaging the strings for adjusting the string tensions, such that they match the preset tones.
The system is very welcome to the extent that it allows easy and automatic tuning and takes away a large amount of work, especially for inexperienced musicians, but also for professionals. The system has a not insignificant disadvantage, however. Overall it is large and clumsy and requires considerable changes to the body of the guitar, which affects, on the one hand, the acoustics (sound) of the guitar and, on the other, the handling of the guitar (due to the changed weight). Apart from these characteristics, the appearance of the guitar is also changed not insignificantly.
Because the entire guitar forms the resonance body that is responsible for the sound characteristics, the sound characteristics also change when the body is changed. Thus, the previously known system is practically impossible to retrofit in existing instruments, but it is also difficult to integrate into new guitars. In particular, in terms of the sound, two guitar types were to be developed independently from each other in the design work, one guitar with the known device and one without.
In WO 03/012774 A1, an electronic device for automatic tuning of a guitar is disclosed, which shows a division of components on the head and the body of the guitar. For this device, for data transfer there is either wiring between the separated components, which represents an intense intrusion into the guitar, with all of the consequences for the guitar sound listed above, or a radio, infrared, or some other type of wireless transmission. For this purpose, however, a corresponding transmitter/receiver must also be attached to the head, which brings with it additional weight and can interfere with the appearance and also the sound response of the guitar. Furthermore, this transmitter/receiver must be provided with a standalone power supply, i.e., a battery or even a power-supply cable connection is to be provided on the head of the guitar.